Thickener



May 9, 1933. A. c. DAMAN 1,907,746

THICKENER Filed June 25, 1928 2 Sheets-Sheet l May 9, 1933.

A. c. MAN

THICKENER Filed June 25, 1928 2 Sheets-Sheet 2 \I//////////////////////////ML Jwnkw Patented May 9, 1933 PATENT orricaARTHUR C. DAMIAN, OF DENVER, COLORADO THIGKENER Application filed June25,

This invention relates to thickeners of the type employed for settlingout the suspended matter from the solutions in mining and millingoperations. Thickeners of this type usually comprise a relatively largesettling tank having a central sand discharge at the bottom and aperipheral solution overflow at the top. Arms, carrying scrapers, arerotated in the tank so as to gradually work the settled sands toward thesand discharge. It often happens that the feed of sand is so excessivethat the arms and scrapers will become imbedded and the operatingshaftand mechanism will be so overloaded as to 5 become damaged. Shouldthe sand become deep enough to stop the arms it is impossible to startthem without first cleaning the tank by hand.

The principal object of this invention is to so construct the armsthatthey will automatically accommodate themselves to the depth of the. sanddeposit in the bottom of the tank, that is, as the sand becomes deeperand the resistance to the rotation increases, the arms will automaticallswing upwardly toward the upper sur ace of the sand until a position ofless resistance is encountered. i

Another object of the invention is to arrange the arms so that they'-will gradually return to their normal position as the sand deposit isdecreased.

A further object of the invention is to provide alarm means which willgive the operator a warning that the sand deposit is increasing so thathe can attend the machine should erate.

Other objects and advantages reside in the detail construction of theinvention, which is designed for simplicity, economy, and efiiciency.These will become more ap parent from the following description.

# In the following detailed descriptipil of the invention reference ishad to the accompanying'drawings which form a part hereof. Like numeralsrefer to like partsin all views of the drawings and throughout the Idescription.

. tank 10; san

the automatic arms fail to op-- 1928. Serial No. 288,015.

In the drawings:

Fig. 1 is a plan view of a typical thickener tank illustrating theinvention in place therein.

Figs. 2 and 3 are detail views illustrating a plan and side elevationrespectively, of the novel hinge joint employed between th sections ofthe thickener arms.

Fig. 4 is a detail view illustrating the contact device for the alarmmechanism.

Fig. 5 is an enlarged fragmentary vertical section through the thickenertank of Fig. 1.;

\ Figs. 6 and 7 are detail views illustrating a side elevation and planview respectively, of an alternate form of hinge joint for the. 35thickener arms.

In the drawings the usual parts of a thickener are designated bynumeral'as follows:

discharge 11; solution overflow trough 12, feed box 13; drive shaft 14;shaft supporting frame 15; shaft worm wheel 16; and worm drive 17.

In applying my invention, I provide thickener arms formed of a pluralityof sections such as indicated at 18." These sections are hinged togetherby means of hinges, designated in their entirety by the numeral 19. Thefirst hinge 19 of each arm is preferably carried from an arm casting 20,secured to the shaft 14. Each of the sections 18 carry the usualangularly placed rakes or scrapers 21, for raking the sand toward thesanddischarge 11. a t

The construction of the hinges 19 is novel and results'in the advantagesclaimed for this invention. In the preferred form of hinge, illustratedin Figs. 2 and- 3, relatively long hinge plates 22' are secured tooneside ofthe sections 18 and relatively short similar plates 23 aresecured to the other side thereof. A hinge pin 24 passes through all, ofthe plates.

The pin. 24 is placed at an angle to the surface plane of the sections18, thatis, it will be closer to the sections at the plates 23 than atthe plates 22. This placement of the hinge pin causes theouter sections18 to use when pressure is brought against their forward surfaces. Forinstance, assume pressure to be'acting against the right-hand section 18as indicated by the arrow A in Fig. 2. Thispressure will act upon theangularly placed hinge pin so as to cause the right hand section toswing rearwardly and upwardly about the pin. Therefore, as the armsencounter resistance, this resistance will cause the arm sections toswing rearwardly as indicated by the broken line position in Fig. 1, andupwardly as indicated by the solid line position in Fig. 5. This causesthe scra ers to rise to the top of the sand deposit w ere they willencounter less resistance and heiree to rotate. As they scrape away thesand the arms will follow the lowering surface to their revious normalor aligned position as indicated by broken line in Fig. 5. -Whenin thealigned position the sections butt together, as lndicated in Fig. 3, toprevent further .dwn ward movement.

Usually the weight of the arms is suflicient to bring them to theirnormal position as the sand surface lowers. Should a more rapid oerationbe desired, however, springs can he placed at each of the hinges1 9. These springs are stretched between angle clips 26 on the sections18 and act. to maintain the hinges cl0sed'and.the section extremitiesagainst each other in the position of Fig. 3. The tension of the springscan be adyusted by means of tension nuts 27.

Brace chains 28 can be employed so as to assist the first hinge 19 insupporting the wei ht of the arms. As the arms rise these chains willsag and'as the arms lower they will ti hten to support the weightthereof.

In i 6 and I have illustrated an alternate orm of the hinge. In thisform the hinge pin which is indicated at 24', is placed at a doubleangle, that is, it ispositione at an angle from the horizontal similarlyt the previous hinge pin 24, but is also place at an an le w the line oftravel of the arms. The alternate hinge functions similarly. to thefirst hinge but acts to maintain the scrapers 21 in a more horizontalposition when the arms are raised u wardl It has been found t at if theangle of the hin e pin 28, from a line normal to the axis of the arm,equals the angle of the pin from a horizontal plane the scrapers 21 willmaintain themselves substantially horizontal at any position of thearms. The alternate form of hinge can also be provided with a spring 29extending at rig t angles to the hinge pin provided with an adjustingnut 30. i

Ordinarily the. hinged arm sections 18 will automatically accommodatethemselves A to the sand volume in the tank 10 but should they fail todo so an alarm mechanism, indicated in Figs. 4 and 5, is provided.

Thealarm mechanism com ri es a relatively long contact blade 31 rm yfixed to the shaft 14 by means of a clamp collar 40 and a set screw 33.The extremity of the arm 31 is provided with an electrical contact screw32 which makes contact with a second similar screw 33. The screw 33 iscarried in an insulated bushing 34 supported from a collar 35 on theshaft 14. The collar 35 also carries a collecting rin 36 to whichcurrent is carried b means of any suitable brush mechanism The ring 36is electrically connected to the screw 33. The brush 37 and the shaft 14are connected in circuit with an. indicating bell 38 and battery 39. Thebell 38 and the shaft 14 are grounded.

In operation, increased resistance to the swing of the arms in thethickener tank 10 will cause the shaft 14 to twist slightly. The twistof the shaft between the collars 40 and 35will cause the arm 31 to bringthe two contact screws 32 and 33 together. This will close the electriccircuit to the bell 38 and give an audible alarm that the shaft 14 isoverloaded.

The specific form of hinges illustrated in Fi 2, 3, 6, and 7 are simplyillustrative. 0t er means could be employed than the hinge lates 22 and23 and the hinge pin 24 could e replaced b separate pivots at each sideof the arms. These changes are simply details of construction and arewithin the spirit of the invention so lon' as the axis- 7 of the hingeis at an angle to either or both the plane of the arms 18 or the axisthereof.

The invention has been described as em taining to a thickener. It can berea 11y: comprehended, however, that its advantages are not limited to athickener but will be equally useful in" any type of mechanism havingarms whichrake material toward a discharge, such as a classifier, asettling: tank, or conveyor feeding mechanism such as employed in grainelevators and the like. It is, therefore, to be understood that the wordthickener as a pearing throughout this specification an in thefollowingclaims, includes all such mechanisms.

While a specific form of the improvement has been described andillustrated herein, it is desired to be understood that the same may bevaried, within the scope of the appended claims, without departing fromt e spirit of the invention.

Having thus described-the invention, what I claim and desire secured byLetters Patent is 1. An arm adapted to rake material toward a dischargefor thickeners comprising a series of sections hinged together; meansfor stopping the rotation about said hinges in one direction when saidarm sections are substantially in alignment; and spring means fordrawing said arm sections into alignment, one extremity of said armbeingfree-to rise above the other extremity.

2. In a mechanism having a vertical shaft 130 adapted to rotate within atank, and arranged to operate rakes for raking material toward adischarge in said tank: an arm section hinged to said shaft so as toswing upwardly; a flexible medium connecting said arm section to saidshaft so as to limit its downward movement; and a series of arm sectionshinged to said first section.

3. In a mechanism having a vertical shaft adapted to operate rakes forraking material toward a discharge: an arm section hinged to said shaftso as to swing upwardly; a flexible medium connecting said arm sectionto said shaft so as to limit its downward movement; a series of armsections hinged to said first section; and means for preventing saidseries of sections from swinging below a position of alignment.

4. In a mechanism having a vertical shaft adapted to rotate within atank and operate rakes for raking material toward a discharge means forcarrying said rakes comprising: an arm section hlngedly supported bysaid shaft so as to swing upwardly; a

flexible medium connecting said arm section to said shaft so as to limitits downward movement; a series of arm sections hinged to said firstsection; and means for causing said hinges to swing said sectionsupwardly 0 when they encounter a resistance.

5. In a mechanism having a vertical shaft adapted to rotate within atank and operate rakes for raking material toward a discharge means forcarrying said rakes com-,

prising: an arm section hinged to said shaft so as to swing upwardly; aflexible medium connecting said arm section to said shaft so as to limitits downward movement; a series of arm sections hinged to said firstsection; and means for causing said hinges to swing said sectionsupwardly when they encounter a predetermined resistance, said meanscomprising the positioning of. the hinge axis at an angle to ,the.horizontal.

In testimony whereof, I' aflix my signature.

ARTHUR C. DAMAN.

